U.S. patent number 10,864,682 [Application Number 15/911,683] was granted by the patent office on 2020-12-15 for method of joining of polymeric composites.
This patent grant is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS LLC. The grantee listed for this patent is GM GLOBAL TECHNOLOGY OPERATIONS LLC. Invention is credited to Bradley J. Blaski, Steven Cipriano, Richard C. Janis, Pei-chung Wang.
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United States Patent |
10,864,682 |
Cipriano , et al. |
December 15, 2020 |
Method of joining of polymeric composites
Abstract
A method of joining first and second layers of polymeric
composite material includes disposing a portion of a molded insert
having a bottom end into a top surface of a first layer of material
and then applying a layer of adhesive between the top surface of
the first layer and a bottom surface of a second layer of material
to create a bond-line thickness. Next, a top surface of the second
layer is pierced with a headless end of a fastener and interlocked
into the molded insert. A layer of protective coating is then
applied to the top surface of the second layer of material to cover
the interlocked fastener.
Inventors: |
Cipriano; Steven (Chesterfield
Township, MI), Blaski; Bradley J. (Sterling Heights, MI),
Janis; Richard C. (Grosse Pointe Woods, MI), Wang;
Pei-chung (Troy, MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
GM GLOBAL TECHNOLOGY OPERATIONS LLC |
Detroit |
MI |
US |
|
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS
LLC (Detroit, MI)
|
Family
ID: |
1000005242718 |
Appl.
No.: |
15/911,683 |
Filed: |
March 5, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190270258 A1 |
Sep 5, 2019 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C
65/48 (20130101); B29C 66/7212 (20130101); B29C
65/561 (20130101); B29C 66/30321 (20130101); B29C
66/30325 (20130101); B29C 66/02 (20130101); B29K
2705/00 (20130101); B29K 2907/04 (20130101) |
Current International
Class: |
B29C
65/56 (20060101); B29C 65/48 (20060101); B29C
65/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"High-performance lightweight structures with fiber reinforced
thermoplastics and structured metal think sheet", published on Nov.
24, 2014, p. 30, 2.2 flow drill joining concept and p. 33, 3.2
global in-plane fiber alignment; published by Canadian center of
science and education (Year: 2014). cited by examiner.
|
Primary Examiner: Aftergut; Jeffry H
Assistant Examiner: Lee; Jaeyun
Claims
What is claimed is:
1. A method of joining first and second layers of material, the
method comprising: disposing a portion of a molded insert having a
bottom end into a top surface of a first layer of material;
applying a layer of adhesive between the top surface of the first
layer and a bottom surface of a second layer of material to create
a bond-line thickness; piercing through a top surface of the second
layer of material with a headless end of a fastener; interlocking
the headless end of the fastener into the molded insert; and
applying a layer of protective coating to the top surface of the
second layer of material to cover the interlocked fastener.
2. The method of claim 1 wherein the fastener is a flow screw.
3. The method of claim 2 further comprising positioning the first
and second layers on a fastener insertion machine after applying
the adhesive layer between the first and second layers and before
piercing the second layer of material with the headless end of the
flow screw.
4. The method of claim 3 further comprising interlocking the flow
screw until the headless end pierces the bottom end of the molded
insert.
5. The method of claim 1 wherein the first and second layers each
include a carbon fiber composite material.
6. The method of claim 1 wherein the bond line thickness is in a
range of 0.1 mm to 1.5 mm.
7. The method of claim 1 further comprising allowing a top end of
the molded insert to protrude above the top surface of the first
layer of material a predetermined distance equal to the bond-line
thickness.
8. The method of claim 1 further comprising allowing the adhesive
layer to at least partially cure.
9. The method of claim 8 further comprising piercing through a top
surface of the second layer of material with a headless end of the
fastener after the adhesive layer is at least partially cured.
10. A method of joining first and second layers of material, the
method comprising: disposing a portion of a molded insert having a
bottom end into a top surface of a first layer of material;
applying a layer of adhesive between the top surface of the first
layer and a bottom surface of a second layer of material to create
a bond-line thickness; piercing through a top surface of the second
layer of material with a headless end of a flow screw; interlocking
the headless end of the flow screw into the molded insert; and
applying a layer of protective coating to the top surface of the
second layer of material to cover the interlocked flow screw.
11. The method of claim 10 further comprising positioning the first
and second layers on a fastener insertion machine after applying
the adhesive layer between the first and second layers and before
piercing the second layer of material with the headless end of the
flow screw.
12. The method of claim 11 further comprising interlocking the flow
screw until the headless end pierces the bottom end of the molded
insert.
13. The method of claim 10 wherein the first and second layers each
include a carbon fiber composite material.
14. The method of claim 10 wherein the bond line thickness is in a
range of 0.1 mm to 1.5 mm.
15. The method of claim 10 further comprising allowing a top end of
the molded insert to protrude above the top surface of the first
layer of material a predetermined distance equal to the bond-line
thickness.
16. The method of claim 10 further comprising allowing the adhesive
layer to at least partially cure.
17. The method of claim 16 further comprising piercing through a
top surface of the second layer of material with a headless end of
a flow screw after the adhesive layer is at least partially
cured.
18. A method of joining first and second layers of material, the
method comprising: disposing a portion of a solid molded insert
having a bottom end into a top surface of a first layer of
material; applying a layer of adhesive between the top surface of
the first layer and a bottom surface of a second layer of material
to create a bond-line thickness; piercing through a top surface of
the second layer of material and the molded insert with a headless
end of a fastener; interlocking the headless end of the fastener
into the molded insert; and after the step of interlocking,
applying a layer of protective coating to the entire top surface of
the second layer of material to cover the interlocked fastener.
Description
FIELD
The present disclosure relates to methods of joining polymeric
composites and other materials using flow screws or other suitable
fasteners.
BACKGROUND
The background description provided here is for the purpose of
generally presenting the context of the disclosure. Work of the
presently named inventors, to the extent it is described in this
background section, as well as aspects of the description that may
not otherwise qualify as prior art at the time of filing, are
neither expressly nor impliedly admitted as prior art against the
present disclosure.
Carbon fiber reinforced thermoplastics (CFRTP) such as carbon fiber
reinforced nylon composites have a high strength-to-weight ratio
and high corrosion resistance, which makes these materials
desirable for use in automotive applications. For example, to
reduce vehicle weight, these materials have been used in parts such
as air intake manifolds, air filter housings, resonators, timing
gears, radiator fans, truck beds and radiator tanks. Despite these
advantages, the number of applications for CRFTP materials is
limited due to the current processes available for joining CRFTP
materials. Therefore, a need exists for improved processes for
joining CRFTP materials.
SUMMARY
One or more exemplary embodiments address the above issue by
providing a method of joining first and second layers of
material.
According to an aspect of an exemplary embodiment, a method of
joining first and second layers of material includes disposing a
portion of a molded insert having a bottom end into a top surface
of a first layer of material. Another aspect includes applying a
layer of adhesive between the top surface of the first layer and a
bottom surface of a second layer of material to create a bond-line
thickness. And another aspect includes piercing through a top
surface of the second layer of material with a headless end of a
fastener. And yet another aspect includes interlocking the headless
end of the fastener into the molded insert. And still another
aspect includes applying a layer of protective coating to the top
surface of the second layer of material to cover the interlocked
fastener.
A further aspect in accordance wherein the fastener is a flow
screw. And another aspect includes positioning the first and second
layers on a die after applying the adhesive layer between the first
and second layers and before piercing the second layer of material
with the headless end of the flow screw. Still another aspect
includes interlocking the flow screw until the headless end pierces
the bottom end of the molded insert. Yet another aspect wherein the
first and second layers each include a carbon fiber composite
material. And yet another aspect wherein the bond line thickness is
in the range of 0.1 mm to 1.5 mm. And still another aspect includes
allowing a top end of the molded insert to protrude above the top
surface of the first layer of material a predetermined distance
equal to the bond-line thickness. And one other aspect includes
allowing the adhesive layer to at least partially cure. And still
one other aspect includes piercing through a top surface of the
second layer of material with a headless end of a flow screw after
the adhesive layer is at least partially cured.
Further areas of applicability of the present disclosure will
become apparent from the detailed description, the claims and the
drawings. The detailed description and specific examples are
intended for purposes of illustration only and are not intended to
limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure will become more fully understood from the
detailed description and the accompanying drawings, wherein:
FIG. 1A is an illustration of a first layer of material having a
molded insert disposed in a top surface in accordance with an
exemplary embodiment of a method for joining first and second
layers of materials;
FIG. 1B is an illustration of the first layer of material and
molded insert of FIG. 1A further including an adhesive layer
applied to the top surface of the first layer in accordance with
aspects of the exemplary embodiment;
FIG. 1C is an illustration of FIG. 1B further including a second
layer of material and a joining fastener in accordance with aspects
of the exemplary embodiment;
FIG. 1D is an illustration of FIG. 1C wherein the first and second
layers of material are joined and a layer of protective coating
covers the top surface of the second layer of material in
accordance with aspects of the exemplary embodiment; and
FIG. 2 is a flow diagram for a method of joining first and second
layers of material as according to the exemplary embodiment.
In the drawings, reference numbers may be reused to identify
similar and/or identical elements.
DETAILED DESCRIPTION
One process for joining CRFTP materials is with a fastening process
such as flow screw insertion. In this process, a flow screw is
inserted into multiple layers of material (or workpieces) to join
the layers together. The materials layers may include, but not
limited to, all polymeric composites, polymers, polymeric
composite-metal combinations. The flow screw includes a head and a
headless end or tail designed to pierce through material. When the
flow screw is inserted downward into the layers, the headless end
pierces through the top layer and then into the bottom layer.
However, it is common that this type of mechanical fastening of
layers of CRFTP materials have low joint strength in addition to
the fastened joints being susceptible to weakening due to
galvanized corrosion over time.
A process for joining first and second layers of materials, more
particularly CRFTP materials, according to aspects of the exemplary
embodiment addresses these issues by using a flow screw and a
molded insert that are designed so that the headless end of the
flow screw penetrates into and through a top layer of material and
then becomes interlocked into a molded insert disposed in a bottom
layer of material. The molded insert serves to improve the
mechanical interlock between the flow screw and the layers of
materials and the overall joint quality. The molded insert can be
made of various materials. The basic necessity is that the molded
Insert must be harder than the composite material that it is molded
into and softer than the fastener that will be inserted into it,
e.g., metal, hardened metal and polymer composites. The size of the
molded insert can vary. It can be small for insertion of one
fastener or be large/long for inserting multiple fasteners, e.g., a
strip along a part flange. The molded insert can also be applied to
a single sheet of material or be involved with multiple material
stack ups without exceeding the scope of the exemplary
embodiment.
Referring now to FIGS. 1A, 1B, 1C, and 1D, an example of a flow
screw joining process for joining multiple layers of material is
illustrated. In this process, a top surface 12 of a first layer 10
of material having a thickness in the range of 0.5 mm-6 mm is
disposed with a portion of a molded insert 15 having a bottom end
14. The molded insert 15 may be integrated into the first layer of
material 10 as part of a material fabricating process, e.g.,
molding, or may be inserted in the material through a separate
secondary process known to those skilled in the art.
FIG. 1B illustrates the top surface 12 of the first layer of
material 10 and the molded insert 15 being covered with an adhesive
layer 20 to create a bond-line thickness 22. A top end 17 of the
molded insert 15 is preferably allowed to protrude above the top
surface 12 of the first layer of material 10 a predetermined
distance equal to the bond-line thickness 22 such that after the
joining process the protruded portion of the molded insert 15
serves to maintain the bond-line thickness 22.
Referring now to FIG. 1C, a bottom surface of a second layer of
material 25 is placed on the adhesive layer 20 and preferably
allowed to partially cure before inserting the flow screw 30. The
first 10 and second 25 layers may be relatively flat sheets having
a thickness in the range of 0.5 mm-6 mm, and placed onto a fastener
insertion machine (not shown). The flow screw 30 includes a
headless end 32 which pierces through a top surface of the second
layer of material 25 with the headless end 32. The headless end 32
of the flow screw 30 is sharp such that when the flow screw 30 is
spun at high speeds and under an axial load it easily penetrates
into the second layer of material 25.
FIG. 1D illustrates the first 10 and second 25 layers of material
after the joining process is complete. After piercing through the
second layer of material 25 the flow screw 30 is aligned such that
the headless end 32 becomes interlocked into the molded insert 15
until the headless end 32 pierces the bottom end 14 of the molded
insert 15. Typically, mechanical fasteners have low joint strength
in composite to composite joints but by introducing the molded
insert 15 into the joining process as according to the exemplary
embodiment the mechanical joint is improved and the bond-line
thickness can be maintained. After the joining process is complete,
a layer of protective coating is applied to the top surface 12 of
the second layer of material 25 to cover the interlocked flow screw
30. This seals the flow screw so that water would not get into the
interfaces between the screw and CFRTP. As a result, the galvanic
corrosion (i.e., corrosion damage induced on steel) can be
minimized.
Referring now to FIG. 2, a method 50 for joining first and second
layers of material is provided. This method is suitable for joining
different types of layered materials but is notably a preferred
method for joining CRFTP material or similar polymeric
composites.
At block 55, the method begins with disposing a portion of a molded
insert 15 having a bottom end 14 into a top surface 12 of a first
layer of material 10.
At block 60, the method continues with applying a layer of adhesive
20 between the top surface 12 of the first layer of material 10 and
a bottom surface of a second layer of material 25. Next, at block
65, the adhesive layer 20 is allowed to at least partially
cure.
At block 70, the method continues with piercing through a top
surface of the second layer of material 25 with a headless end 32
of a flow screw 30 after the adhesive layer 20 is at least
partially cured.
At block 75, the headless end 32 of the flow screw 30 is
interlocked into the molded insert 15 disposed in the first layer
of material 10.
Finally, at block 80, the method ends with applying a protective
coating 35 to the top surface of the second layer of material 25 to
cover the interlocked flow screw 30.
The foregoing description is merely illustrative in nature and is
in no way intended to limit the disclosure, its application, or
uses. The broad teachings of the disclosure can be implemented in a
variety of forms. Therefore, while this disclosure includes
particular examples, the true scope of the disclosure should not be
so limited since other modifications will become apparent upon a
study of the drawings, the specification, and the following claims.
It should be understood that one or more steps within a method may
be executed in different order (or concurrently) without altering
the principles of the present disclosure. Further, although each of
the embodiments is described above as having certain features, any
one or more of those features described with respect to any
embodiment of the disclosure can be implemented in and/or combined
with features of any of the other embodiments, even if that
combination is not explicitly described. In other words, the
described embodiments are not mutually exclusive, and permutations
of one or more embodiments with one another remain within the scope
of this disclosure.
Spatial and functional relationships between elements (for example,
between modules, circuit elements, semiconductor layers, etc.) are
described using various terms, including "connected," "engaged,"
"coupled," "adjacent," "next to," "on top of," "above," "below,"
and "disposed." Unless explicitly described as being "direct," when
a relationship between first and second elements is described in
the above disclosure, that relationship can be a direct
relationship where no other intervening elements are present
between the first and second elements, but can also be an indirect
relationship where one or more intervening elements are present
(either spatially or functionally) between the first and second
elements. As used herein, the phrase at least one of A, B, and C
should be construed to mean a logical (A OR B OR C), using a
non-exclusive logical OR, and should not be construed to mean "at
least one of A, at least one of B, and at least one of C."
None of the elements recited in the claims are intended to be a
means-plus-function element within the meaning of 35 U.S.C. .sctn.
112(f) unless an element is expressly recited using the phrase
"means for," or in the case of a method claim using the phrases
"operation for" or "step for."
* * * * *